Mechanisms of action of protein synthesis and secretion were studied in acinar cells of the rat parotid. Monoclonal antibodies to Alpha-amylase purified from rat parotid secretory granules were purified and characterized using chromatographic and solid phase immunosorbent (ELISA) techniques. Preparation of mRNA from the salivary gland was carried out and measurement of total and specific (immunoreactive with anti Alpha-amylase reagent) translation products served as an index of protein synthetic responses to in vivo Beta-adrenergic stimulation of the animal with isoproterenol. The pharmacologic agent forskolin was useful for in vitro stimulation of parotid acinar tissues. The effects of the secretagogue on cellular signal processing were determined. a) morphologically (LM, EM) b) biochemically (cAMP-dependent protein phosphorylative reactions and specific enzyme distributions). Exocytosis can be regulated by agents which either undergo receptor interactions or involve cell membrane adenylate cyclase directly. Mechanisms of action of these stimuli appear to be cyclic AMP-dependent reactions involving gene regulation by cyclic AMP-mediated phosphorylative modification of variously compartmentalized cellular proteins. Physiologically these reactions are cellular manifestations of stress responses in general, but specifically involve oral soft tissues.